If you're referring to the barrier that separated communist countries in Europe from non-communist countries, the answer is the Berlin Wall.
Three nations divided into communist and non-communist were Germany, Korea and Vietnam(until it became completely communist)
Russia was the only country to become communist during World War 1.
Soviet Union, China Korea
US and all of western europe
The Domino Theory was a geopolitical idea during the Cold War that suggested if one country in a region fell to communism, then neighboring countries would also fall like dominoes. This theory was used to justify U.S. involvement in conflicts such as the Vietnam War in an effort to prevent the spread of communism.
If you're referring to the barrier that separated communist countries in Europe from non-communist countries, the answer is the Berlin Wall.
Czechoslovakia
Russia. They became communist during Lenin's reign.
china
These countries had communist governments that were controlled by the Soviet Union.
These countries had communist governments that were controlled by the Soviet Union.
Japan
north korea
Three nations divided into communist and non-communist were Germany, Korea and Vietnam(until it became completely communist)
Communist countries during the Red Scare include Russia, China, Eastern Europe, and Korea. The Cincinnati Reds baseball team changed their name to the "Redlegs" during the scare so their name wouldn't be associated with communism.
As a communist nation, China became part of the global communist alliance lead by the USSR. Western nations were in conflict with the communist bloc during the Cold War.